1919a4.com
- A forum-based site with information about Browning military 1919a4 and 1919a6 rifles. Includes conversion information for 1919 series belt fed machine gun parts kits to legal semi-auto rifles.

The AK Files
- A forums-based site primarily aimed at home building AK variant rifles. Some coverage of other firearms building. Information, advise and vendors.

BATF - Firearms Section
- Dept. of Justice, BATF site. An important resource for legal information about making firearms without violating federal laws.